There are two size of Jaw exerciser, Large for mens and Small for womens. Product size & measurement check product images details. Material: Jaw exerciser and neck toning equipment made of food-grade silicone to ensure safety. polyurethane bite strip allow for a custom mold to your mouth that allows you to easily adjust the shape and mouth cavity Effect: Jaw exerciser and neck toning equipment tones and tightens underlying facial muscles to help reverse the signs of aging. exercises facial muscles to reduce sagging, wrinkles and smile lines, looks younger and better. reduce hunger, it has been shown to reduce cravelling, resulting in more weight loss. Be Applicable: a younger, tighter face, increased metabolism, increased hair growth, stress relief, Increased levels of human growth hormone, and ending oral fixations to name Lightweight and Convenient: Jaw exerciser chew has been shown to reduce cravings, leading to more weight loss. Convenient, hands-free exercises, easy to carry, can be used when going out, gym, work, and use anywhere.